• Journal of Korea Water Resources Association
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• v.37 no.1
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• pp.13-19
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• 2004

This study shows the possible use of the Poisson process for the characterization of dry year return period and duration. For the analysis we used an annual precipitation data, which has been collected since 1911 in Seoul. The highest threshold for the application of the Poisson process was determined to be the mean-0.5standard deviation, and then the results from the Poisson process are compared with the observed. Especially, the Poisson process was found to reproduce the mean duration and return interval quite well and show the possibility of using the Poisson process for the drought analysis.

• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.2
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• pp.77-81
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• 1989

This experiment was conducted to elucidate the changes of dry matter production in permanent pasture and its relation with relative yield of the 1st cutting, regrowth capacity, and persistance of orchardgrass sward, based on the data of preceeding The results were summarized as follows; 1. Relationship between relative yield of the 1st cutting and regrowth capacity were changed by the times of established pasture. Thus, the relative yield of the 1st cutting have negative significant correlation (P < -0.001) with regrowth capacity. 2. Regrowth capacity(RC) was positively significant correlations with the dry weight of plant (DW/pl.), number of tillers per plant (NT/pl.), plant size(PS) and distance between adjacent plants (DIS) of the 1st cutting. Also, regrowth capacity(RC) was positively correlations with the dry weight of plant (DW/pl.), number of tillers per plant (NT/pl.), stubble diameter(DIA), stubble area(SB), plant size(PS) and distance between adjacent plants(D1S) of the 2nd cutting. 3. The coefficients of regression of the 1st cutting showed a tendency to slightly decrease, on the other hand, the 2nd cutting and total yield were tended to increase by the times of established pasture. 4, Between the regrowth capacity and persistency were may deeply concerned to the changes of dry matter production in permanent pasture. 5. The process of dry matter production in permanent pasture can be shown in following diagrams.

• Journal of environmental and Sanitary engineering
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• v.23 no.3
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• pp.9-22
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• 2008

This study was conducted to develop a system that processes harmful gases and dust, which being generated in the production of micro-inorganic fabric. This can be obtained by melt spinning raw materials such as agalmatolite, fluorspar, limestone, silica under high temperature at $1500-1600^{\circ}C$ in a glass recuperator using a dry method by Cyclone Reactor or Envelope Type (ET) type Bag Filter. If the number of the members of Korea Glass Industry Association reaches up to 45, the damage of the harmful gas being generated in recuperator should not be small. In addition, research of existing facilities showed the most of harmful gas treatment facilities which adopt wet treatment or semi-dry treatment process. This was caused the problems for wastewater and the second pollutive materials. Moreover, in the dust collecting facility behind recuperator, it is also problematic that electric dust collector requires enormous initial investment. We have researched various methods to show both economic and efficient new processes for the preventive facilities of recuperator. As the result of the experiments, the removal efficiencies of HF and SOx were 99% and 87%, respectively. Although it was insignificant reaction, a pretty much interesting result that NOx showed an absorption reaction with $Ca(OH)_2$(removal efficiency was more than 25%) was obtained.

• Journal of Environmental Science International
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• v.32 no.2
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• pp.121-130
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• 2023

This study was conducted to investigate changes in seed vigor based on temperature of dry heat and duration treatment of watermelon seeds and examine the effect on percent of emergence and seedling vigor. When the upper limit temperature of dry heat treatment was raised to 80℃, the percent of the germination decreased. Moreover, T₅₀ was delayed as the upper limit temperature of dry heat treatment increased. The higher the upper limit temperature of dry heat treatment and the longer the treatment period, the higher the percentage of abnormal seedlings. The optimum upper limit temperature for dry heat treatment was 72℃, and the treatment period was five days. Seed vigor was better maintained at 30℃, 45℃, and 52℃, followed by stepwise exposure to high temperatures of 72℃, the upper limit of dry heat treatment, rather than dry heat treatment at a high temperature of 72℃ for 5 days from the initial stage of treatment. When the fungicide was added during the dry heat treatment process, the germination percentage decreased and the percent of the abnormal seedling percentage increased. However, the addition of 10 mg/kg fungicide did not significantly reduce seed vigor.

• Industrial Engineering and Management Systems
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• v.9 no.3
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• pp.242-250
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• 2010

For economical and environmental reasons, the aim of this research is hence to monitor the cutting conditions with the dry cutting, the wet cutting, and the mist cutting to obtain the proper cutting condition for the plain carbon steel with the ball end milling based on the consideration of the surface roughness of the machined parts, the life of the cutting tools, the use of the cutting fluids, the density of the particles of cutting fluids dispersed in the working area, and the cost of cutting. The experimentally obtained results of the relation between tool wear and surface roughness, the relation between tool wear and cutting force, and the relation between cutting force and surface roughness are correspondent with the same trend. The phenomena of surface roughness and tool wear can be explained by the in-process cutting forces. The models of the tool wear with the cutting conditions and the cutting times are proposed to estimate the tool cost for the different cooling strategies based on the experimental data using the multiple regression technique. The cutting cost is calculated from the costs of cutting tool and cutting fluid. The mist cutting gives the lowest cutting cost as compared to others. The experimentally obtained proper cutting condition is determined based on the experimental results referring to the criteria.

• Journal of Sensor Science and Technology
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• v.32 no.1
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• pp.31-38
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• 2023

Three-dimensional (3D) micro/nanostructures based on soft elastomers have received extensive attention in recent years, owing to their potential and advanced applicability. Designing and fabricating 3D micro/nanostructures are crucial for applications in diverse engineering fields, such as sensors, harvesting devices, functional surfaces, and adhesive patches. However, because of their structural complexity, fabricating soft-elastomer-based 3D micro/nanostructures with a low cost and simple process remains a challenge. Bio-inspired designs that mimic natural structures, or replicate their micro/nanostructure surfaces, have greatly benefited in terms of low-cost fabrication, scalability, and easy control of geometrical parameters. This review highlights recent advances in 3D micro/nanostructures inspired by nature for diverse potential and advanced applications, including flexible pressure sensors, energy-harvesting devices based on triboelectricity, superhydrophobic/-philic surfaces, and dry/wet adhesive patches.

• Journal of Microbiology and Biotechnology
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• v.1 no.2
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• pp.111-115
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• 1991

The green alga, Dunaliella salina under fed-batch cultivation produced 51.12 mg of hydrocarbon per liter with maintaining 0.313 (g dry wt/l). About 20% of hydrocarbon production yield based on dry biomass was obtained from both batch and fed-batch processes. Optimum culture conditions of light intensity, pH and salt concentration were obtained as 0.0080 (kJ/$cm^2$/h), 8.0 and 1.4 (g of NaCl/l), respectively by response surface analysis. The production of hydrocarbons in D. salina was closely correlated to cell growth. Fed-batch cultivation produced more hydrocarbons and maintained better cell growth than a batch process.

• Tribology and Lubricants
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• v.25 no.1
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• pp.66-72
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• 2009

Al-based composites reinforced with SiC particulate were fabricated using a thermal spray process, and dry sliding wear behavior of the composites was investigated. Pre-mixed Al and SiC powders were sprayed on an A16061 substrate by flame spraying, and dry sliding wear test were performed under various sliding speed and applied load conditions against ${Al_2}{O_3}$ ball. Wear behavior of the composites was studied by using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). And build-up mechanism of MML on the worn surface of the composites was examined. It was revealed that these MML was formed of debris from the contact surface of the composites and effected to wear behavior of the composites protecting the contact surface of the composites.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.3
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• pp.215-222
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• 2014

This paper presents an experimental study of a vibration-assisted dry micro-wire electrical discharge machining (${\mu}$-WEDM) utilized in high precision and micro-manufacturing area. The assisted vibration was applied to the workpiece using a piezoelectric actuator, and high pressure air was injected directly into the machining gap through a nozzle. Investigation experiments were performed to estimate the importance of input parameters and it was observed from experiment results that the width (kerf) of the cutting slot and the machining time were significantly affected by the air injection pressure and input energy. Moreover, it was also observed that there exists an optimal relationship between the machining time and input parameters including the air pressure and vibration frequency and amplitude. Central composite design based experiments were also carried out, and empirical models of the machining time and cutting slot kerf have been developed using the response surface methodology to analyze and optimize the process.

• Fashion & Textile Research Journal
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• v.16 no.2
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• pp.326-332
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• 2014

To develop cool touch feeling fabrics for summer clothing material, it was manufactured several compositions of woven fabrics, having rayon multi-filament yarn (non-twisted) as warp and various kinds of yarn, such as viscose rayon multi-filament yarn (twisted), tencel$^{(R)}$ spun yarn, PET high absorbance quick dry filament yarn, and PET based rayon-like yarn, as weft. After preparing the fabrics, basic properties of the fabrics were investigated, such as air-permeability, tensile strength, absorption rate, drying rate, etc. Also, surface warm / cool sensations of the woven fabrics were assessed by Qmax Warm / Cool Touch Tester. It was observed that the fabrics composed of viscose rayon multi-filament yarn (warp) and PET high absorbance quick dry filament yarn (weft) showed excellent surface cool touch sensation-the highest Qmax value. This is because the fabric having flat shaped PET high absorbance quick dry filament shows the largest contact area with Qmax measuring plate. And, the fabric also showed superior high absorbance and quick dry property as expected. In addition, we treated phase change material (PCM) on the surface of the fabric composed of viscose rayon multi-filament yarn (warp) and PET high absorbance quick dry filament yarn(weft) to improve the cool touch feeling. However, the surface cool touch feeling was impaired by resin treated with PCM during the finishing process.